1. Technical Field
The present disclosure is directed to a microfluidic delivery system including a die having a plurality of heaters and a plurality of nozzles associated with the heaters, where an area of each heater is significantly larger than an area of each nozzle.
2. Description of the Related Art
Microfluidic die are utilized in printers for ejection of drops of ink onto paper. The die is positioned on an extended end of a cartridge that is separated from a main body that holds a reservoir of the ink. The extended end puts the die in close proximity to the paper to accurately expel the drop of ink to form a word or image on the paper.
FIG. 1 is an enhanced view of a fluidic path from an inlet 7 into a chamber 17 and through a nozzle 11 of a microfluidic die 13 of a known type. The nozzle 11 is formed through a nozzle plate 15 that is positioned over the chamber 17. In this view, the nozzle plate 15 has been cut along a center line of the nozzle to show a cross-section of the nozzle 11. In particular, the nozzle 11 has a lower opening 19 with a first diameter 29 that is significantly larger than a second diameter 31 of an upper opening 21. Walls of the nozzle are sloped between the lower opening 19 and the upper opening 21.
FIG. 2A is a top down view showing relative sizes of elements of the microfluidic die of FIG. 1. FIG. 2B is a cross-section view along line 2B-2B of FIG. 2A. The die 13 includes a heater 23 that is positioned below the chamber 17. The heater 23 has a smaller area than the chamber 17. For example, the heater 23 may be square with sides that each have a first dimension 25 of 30 microns, giving the heater 23 an area of 900 square microns. The chamber 17 is also square, with sides each having a second dimension 27 of 35 microns, giving the chamber 17 an area of 1225 square microns. The nozzle 11 includes the lower opening 19, which is larger than area of the chamber 17. For example, the first diameter 29 may be 50 to 60 microns, giving the lower opening 19 an area of 1962.5 to 2826 square microns. The nozzle 11 includes the much smaller upper opening 21, which has the second diameter 31. This second diameter is 30 microns, giving the upper opening 21 an area of 706.5 square microns.
The lower opening 19 covers a larger area than both the chamber 17 and the heater 23. The relationship between the heater's area and the upper nozzle area are such that drops of ink are consistently formed and dropped downward onto a printing material, such as paper.